Movable dam



June 16, 1931. H. TAHARA MOVABLE DAM Filed June 30, 1928 2 Sheets-Sheet 1 I I I'm 6725111; H. Tahara Alibi-716% k June 16,1931.

H. TAHARA MOVABLE DAM le m 1928 2 Sheets-Sheet 2 R Y n mmm In ventral-.- H. Taker-2 By m Aztarney 8, 8" are provided so that they may revolve inde ndent-ly and at the underneath of the fixed axles 6, 6 are provided the hanging journals 9, 9 which carry the axles at the ends of the dam: these hanging journals carry axles 10 within the same vertical lanes as the fixed axles 6 and 6 (see ig. 1). The axles '10 carry sets of pulleys 11, 11' and 12, 12, the latter being supported so as to be independently rotated.

One end of the wire rope or cable 13, connects to a fixed oint 14 at the side of the hoistin machine, rom which it is run over the pu leys 128"7l17117 8'-128 as shown in Fig. 2, and the other end of the rope or cable is connected to the drum of the hoisting maehine.- When the hoisting machine is operated and the end ofthe rope is wound up, the pullin force will be transmitted with equal speed t rough the length of the rope or cable 13 to both ends 0 the dam. Though the pulley 12 which receives the force through the rope from the hoisting machine is to be pulled up first, the movement of the pulley 12 will be delayed because the pully 12 on the same axle will receive the pulling force at the last moment by the arran ement of the rope, and the pulley 12 waits wlthout moving until the pulleys 11, 11' at the opposite side begin to be pulled up. As soon as the pulleys 11, 11' are ulled up, the pulleys l2, 12 are also pul ed u with the wheels 1 and the dam is rolled up along the guide rails 5. Where hanging chains and anchored chains are used instead ofthe gears and racks, it will be understood from the above that roll-' ing motion is given to the dam in the same sides is the same.

we a I 'l he relative speeds of the re e at the ends of the dam are as follows n Fig. 5, if the weight W of the dam is on the axle X, and the rope is run over several pulleys in the order a, b, c, d, e, f, g, h, z, j, In from thefixed point 0 and k is connected to the hoisting machine, the speed of winding, that is to sa the ratio of speed of the beginning and en of the rope will be 1: 8.

Thus the sums of the respective speeds of the longitudinal portions of the rope at the left and right sides of the dam are equal and the respective tensions of the said longitudinal portions are equal because the number of turns of the rope at the left and right Now as the logitu dinal portions of the rope have the same tensions and speeds and the weights on those portions are the same, both ends of the dam will be pulled up uniformly. Though the above explanation has been given for the case where two pulleys are provided at the sides of the dam, it will be understood that where the number of pulleys is increased to more than two, the operation will be similar to the above. Where, however, the number of pulleys has been increased to more than two, it will sometimes be seen that the sums of the speeds of the longitudinal portions of the rope at the left and ri ht sides are not equal, the gear wheels are 0% extraordinarily large diameter in comparison with the speed of the dam, and the said gears revolving themselves in mesh with the racks, such differences of speed would be automatically adjusted b the slip between the pulleys and their ax es.

The explanation hereinbefore given also applies to the case where han ing and anchored chains are adopted. Since the friction produced between those chains and the dam acts against the rolling of the dam slip will occur between the suspension pulleys and their axes. In view of such a slip, the differential speed of the longitudinal portions of the cable at both sides will be adjusted as in the above case.

What I claim and desire to secure by LettersPatent is:

1. A movable dam, comprising axles and mounted at its ends in 'ournals for rotatable movement; supports or the journals and pulleys operatively mounted in said su ports; a separate set of pulleys operative y mounted in a bridge support and agate to receive said support; a single suspension cable operative with both sets of pulleys, one end of said cable being connected to a fixed point and having operative connection to a hoisting means at its opposite end.

2. A movable dam, provided with axles and mounted in journals at its ends for rotatable movement on said axles; hanging supports for said journals and pulleys operatively mounted ,in' said su ports, sald pulleys constituting a system 0 equal numbers at each end of said dam; a separate system of pulleys mounted in a bridge support in opposing relation to said first-named system of pulleys; a gate bridged by said support; and a single suspension cable operatlve with both systems of pulleys, one end of said cable being connected to a-fixed point in the gate and having operative connection at its opposite end to hoisting means to effect movement of said dam.

3. A movable dam provided wtih axles at its ends and journaled for rotatable movement on said axles; supports for said dam and pulleys operatively mounted in said supports at each end of the dam; a separate system of pulleys in opposing relation to the first-named pulleys and a bridge support for said pulleys; a gate bridged by said support; a single cable operative with both s stems of pulleys to effect movement of the am; a set .of hanging and anchored chains operatively associated with said dam adjacent its ends, the upper end of each hanging chain being connected to a fixed point at the top of the inclined abutments of said gate and the lower end being fixed to a "points on the periphery ofthe dam, one end of each v anchored chain'having fixed connection at points on the periphery of the dam.

4. A movable dam, comprising axles and mounted at its ends in journals for rotatable movement; supports for the journals and pulleys operatively mounted in said sup ports; a separate set of pulleys operatively mounted in a bridge support and agate to receive said support; and a single suspension cable operative with both sets of pulleys, one end of said cable being connected to a fixed point and having operative connection to a hoisting means at the 0pposite end, and the fixed end of the driving cable being at the same side -with'the driving end of the cable and the cable passing over the pulleys of one side and those of the other side. I

In testimony; whereof I have signed my name to this specification. p

a HISAKICHI TAHARA.

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